Based on the L4 Win version that does not have this problem, the apparatus will scroll if linked as well as show up in the apparatus section of the Exegetical Guide. Most importantly it will populate with other Greek texts in the Text Comparison tool.

This is not directly related, but I don't find the SBLGNT in my Library. I downloaded it today (or so I thought) and checked the application support only to see that it shows to have downloaded on the 27th. I don't know if it's indexed or not, how can I tell and what can I do about it if it's not?

Once you've typed "update resources" (as Alan suggested) and you see it in the dropdown box, you can click and drag "Update Resources" from the dropdown over to the right of the command bar. It will create a button you can click to check for resource updates in the future. You can do this with any command.